Update database.py

database.py

@@ -4,6 +4,7 @@
 
 from sklearn.metrics.pairwise import cosine_similarity
 from sqlalchemy import and_, delete, select
+from sqlalchemy.dialects.postgresql import insert
 from sqlalchemy.ext.asyncio import AsyncSession, create_async_engine
 from sqlalchemy.orm import sessionmaker
 
@@ -44,14 +45,10 @@ async def get_or_create_user(self, user_id: str, session: Optional[AsyncSession]
 
     async def _get_or_create_user_in_session(self, session: AsyncSession, user_id: str) -> None:
         """Helper to get or create user within a given session"""
-        query = select(User).where(User.id == user_id)
-        result = await session.execute(query)
-        user = result.scalar_one_or_none()
-
-        if not user:
-            user = User(id=user_id)
-            session.add(user)
-            await session.commit()
+        # Use ON CONFLICT DO NOTHING to atomically create the user if they don't exist
+        insert_stmt = insert(User).values(id=user_id).on_conflict_do_nothing(index_elements=['id'])
+        await session.execute(insert_stmt)
+        await session.commit()
 
     async def add_conversation(self, user_id: str, message: str, response: str, 
                              language: str, embedding: List[float] = None,